Reciprocating valve for double piston concrete pump

ABSTRACT

The present valving apparatus is especially adapted for use in conduits through which construction mixtures, such as concrete mixtures, flow. The valving apparatus is constructed for cooperation with a pump having two pistons in two respective pump cylinders. For this purpose, there are provided a cylindrical valve housing having first ports connected to said pump, second ports connected to conveying conduit means, and third ports connected to supply means, as well as a three member two position valve plug movable back and forth in said valve housing. The valve plug has a central member with a substantially straight passage way and, adjacent to said central member, two end members with curved passage ways, whereby, depending on the position of the valve plug, one of the pump cylinders is connected to said conveying conduit means while the other pump cylinder is connected to the supply means or vice versa.

111 3,889,713 1 June 17, 1975 United States Patent [191 Bender 1 1RECIPROCATINC VALVE FOR DOUBLE PISTON CONCRETE PUMP FOREIGN PATENTS 0RAPPLlCATIONS Horst Bender, Linto rf, Germany WIBAU (WestdeutscheIndustrie-und [75] Inventor:

[73] Assignee:

Primary Examiner-William Cline Strassenbaumaschinen-GesellschaftAttorney, Agent, or FirrizWolfgang G. Fasse; Willard m.b.H.),Rothenbergen, Germany W. Roberts July 13, 1973 221 Filed:

[57] ABSTRACT The present valving apparatus is especially adapted foruse in conduits through which construction mixtures, such as concretemixtures, flow. The valving apparatus ,is constructed for cooperationwith a pump having two [21] Appl. No.: 379,195

[30] Foreign Application Priority Data July 20, 1972Germany............................ 2235586 pistons in two respectivepump cylinders. For this purose, there are provided a cylindrical valvehousing g first ports connected to said pump, second orts connected toconveying conduit means, and third ports connected to supply means, aswell as a .m V a PhD. 76 8 8 mmlww 711 ll 1 65 4 2 6 2.16 G 8 9 76 W ZHM06 v 6 9 /7 0 7 50 3.029 1W 1 rm oo n3 ma ""13 MHZ nm n6 mmCoo m mm "85""82 L TI CGM7 a 3 SL 0 .l U.mF 1 2 1.1 218 555 three member twoposition valve plug movable back and forth in said valve housing. Thevalve plug has a References Cited UNITED STATES PATENTS central memberwith a substantially straight passage way and, adjacent to said centralmember, two end members with curved passage ways, whereby, depending onthe position of the valve plug, one of the pump 2,875,782 3/19593,158,901 12/1964 Westoverm.

nduit cylinders is connected to said conveying co Schumann dto Herion etal... 3/1972 Reinert...............................

means while the other pump cylinder is connecte 17/900 the supply meansor vice versa. 3,682,575 8/1972 Guddal et a1. 417/517 3,749,525

7/1973 Hooper et 417/900 2 Claims, 3 Drawing Figures PATENTEIJJUN 17I975 153,8 8 9,713

SHEET SECTION A-I-B FIG. 2

SECTION1 c +0 RECIPROCATING VALVE FOR DOUBLE PISTON CONCRETE PUMPBACKGROUND OF THE INVENTION The present invention relates to a valvingapparatus for interconnecting a double piston pump having two cylinderswith conveying conduit means and with sup ply means, especially forconveying construction mixtures such as concrete mixtures or the like.

The conventional valving mechanisms for so called concrete double pistonpumps usually comprise flat slide means for closing and opening the pumpcylinders. Preferably, two flat slides are employed, each of which hasits own guide means and which are arranged at a 90 displacement relativeto each other. The guide means are arranged in such a manner that theslides may cooperate with the suction and pressure side of the mixturepassing conduits. In this kind of arrangement, and assuming the normaloperational position of the pump, the vertically aligned slide isarranged for cooperation with the working cylinders of the pump whereasthe horizontally arranged slide cooperates with the supply container forthe mixture to be conveyed. Stated differently, of the four possibleslide positions, two slide positions have to be adjusted simultaneouslyin such a manner that a pressure passage and a suction passage isprovided through the guide and the slide.

It has been found that the above conventional arrangement and manymodifications thereof all have the common disadvantage that flat slidemembers pose, on the one hand a substantial sealing problem while on theother hand, these flat slides are subject to a high wear and tear,especially due to the necessary alternating adjustment of two passagepositions each and two closing or blocking positions each. The high wearand tear of conventional slide valving mechanisms is especially seriousbecause it calls for a frequent replacement of the mostly metallic slideplates which means that not only the plates but also the respectiveguide means must be replaced because the guide means are, of course,also subject to said wear and tear.

The actual useful life of the pump is substantially reduced due to theabove mentioned relatively high wear and tear of the slide means whichis rather higher than the wear and tear of the remaining pump elements.As a result, it is not practical to overhaul the entire pump and all itsparts at uniform time intervals because the maintenance or overhaul workmust be geared to the weakest link in the arrangement, namely the slidevalving mechanism. On the other hand, a random overhaul of theindividual pump elements is respectively subject to down times, whichmay be rather substantial in their accumulation.

A further drawback of prior art arrangements is seen in that the passageways on the suction side as well as on the pressure side are constructedin such a manner that a substantial pressure loss cannot be avoided. Asa result, the consistency of the material to be conveyed must bemaintained within narrow limits. In addition, the conveying distance aswell as the conveying head or lift are substantially reduced due to saidpressure loss.

OBJECTS OF THE INVENTION In view of the foregoing, it is the aim of theinvention to achieve the following objects singly or in combination:

to remove the above outlined disadvantages of the prior art, morespecifically, to provide a valving mechanism which may be efficientlyused in connection with the conveying of rough materials, for example,concrete mixtures in connection with a double piston cylinder pump forthe alternating supply of material to one of the pump cylinders and thedischarge of material from the other pump cylinder or vice versa;

to provide a valving mechanism for the here described enviroment whichis constructed so as to substantially reduce the friction wear and tearto the extent that overhaul and maintenance work may be practicallylimited to be performed at uniform time intervals;

to provide a valving mechanism which avoids the pressure drop along itspassage ways and thus assures a more efficient conveying distance aswell as a better lift;

to construct and arrange the several members of the valving mechanism insuch a manner that the travel or displacement distance of the valveclosure member is substantially reduced, especially in order to therebyalso reduce the wear and tear;

to construct the elements of the valving mechanism and to arrange theseelements relative to each other in such a manner that a simplecontruction is achieved whereby the maintenance and replacement of partsis made easier and simpler; and

to construct the passage ways of the valve closure member as replaceableinserts of high wear resistan. material.

SUMMARY OF THE INVENTION:

According to the invention there is provided a valving apparatus havinga cylindrical valve housing which is preferably arranged to extend withits longitudinal axis at an angle of about relative to the axis of thework cylinders of the above mentioned pump. The valve housing isprovided with two suction or inlet ports for connecting the housing to asupply container. The housing is further provided with two outlet portsfor connecting the valve housing with a conveyor conduit means and twoadditional ports for connection to the working cylinders of the pump.Three valve plugs or valve sections forming preferably an integralpiston type of valve plug are arranged in series with each other, so asto be compatible with the function of suc' tion, pressure, and suctionin that order. The valve plug sections or members forming the ends ofthe integral valve plug are arranged so that one of these end members isclosed by the valve housing while the other end member provides apassage way for the material to be conveyed from the supply means to thecylinder of the pump which at that instance acts as a suction means andvice versa. The plug member arranged intermediate the two end membersprovides a passage way for the flow of the material to be conveyed fromthe cylinde of the pump which at that instance acts as a pressurecylinder for transferring the material to a conveying conduit. The valveplug is movable back and forth between two opposite end positions inresponse to the respective movement of the pump pistons.

Preferably for this purpose, the valve plug is connected to means formoving the valve plug back and forth, for example, by means of a plungerrod connected to one or both ends of the valve plug.

BRIEF FIGURE DESCRIPTION:

In order that the invention may be clearly understood, it will now bedescribed, by way of example, with reference to the accompanyingdrawings, wherein:

FIG. 1 is a longitudinal sectional view through a valving apparatusaccording to the invention;

FIG. 2 is a sectional view along the sectional line A,B of FIG. 1; and

FIG. 3 is a sectional view along the section line CD of FIG. 1.

DETAILED DESCRIPTION OF AN EXAMPLE EMBODIMENT:

FIG. 1 illustrates a longitudinal sectional view through a valvingapparatus according to the invention, whereby the valve housing 1 has acylindrical shape and is provided with port means for the connection toa double piston pump, to a conveying conduit and to a supply container.A valve plug 7 constructed as a piston type three member plug controlsthe action of the valve as will be described in more detail below. Theflow of the material through the valve, for example, a concrete mix, isshown by the dashed line arrows.

The valve housing 1 is closed by cover members 2. A stuffing box andguide bushing 3 is connected to one or both of the cover members 2. Eachguide bushing receives a plunger rod 4 which is connected to the valveplug 7 and which is actuated in response to the operation of the pump,more specifically, in response to the movement of the work pistons ofthe pump. When these pistons reach their respective end positions, thevalve plug is actuated in one or the other direction through well knownlinkage means connected between the pump and the plunger rod or rods 4.Only one plunger rod may also be used.

According to the invention, the valve plug 7 is pro vided with threeseparate sections or plug members including an end member 5, a secondend member and an intermediate member 6. Preferably, these members areconstructed to form an integral valve plug.

As mentioned, the valve housing 1 is provided with first port means 8'and 9' for connecting the valve housing to the respective cylinders 8and 9 of the double piston pump which itself is not shown in detail. Thevalve housing comprises second port means 10 and 11 for connecting thevalve housing to conveying conduit means 20, preferably, with the aid ofa Y-conduit member having two legs 12 and 13 connected to the ports 10and 11 respectively and an outlet port 16. The valve housing is providedwith further port means 14 and 15 which are preferably flanged to asupply container for the material to be conveyed. The container itselfis not illustrated.

Referring to FIG. 2, the intermediate plug member 6 forms preferably astraight passage way from the cylinder 8 to the conduit leg 12. Further,the plug is made of synthetic material, for instance a silicon rubber,and the passage way itself is formed by an insert of a high wearresistant material, such as steel. Preferably, the insert 18 isremovable to facilitate the maintenance of the valve and to prolong itsuseful life.

Referring to FIG. 3, the valve end members 5 or 5 are also made ofsynthetic material, such as silicon rubber, and again an insert 17 isprovided for a passage way through the valve plug. Preferably, theinserts 17 have a bent shape to form a knee as illustrated. Preferably,the ends of the knee include an angle of less than 90, preferably Asmentioned, the valve plug 7 is movable back and forth between two endpositions and the length of the plug from end to end is correlated tothe inner length of the valve housing 1 in such a manner that in eachposition of the valve plug, one of the two passage ways formed by theend plug members is closed by the valve housing 1 while the otherpassage way connects the supply container to the respective pumpcylinder. In the position shown in FIG. 1, the plug member 5'interconnects the supply container with the suction cylinder 9 of thepump and the passage way through the plug member 5 is closed. When theplug 7 is moved in the direction of the horizontal arrow to its otherend position, the situation would be reversed. The central valve plugmember 6 interconnects in the position shown the pressure cylinder 8with the leg 12 of the Y- member. In the other position of the valveplug, the passage way through the central member 6 would be from thecylinder 9 to the leg 13.

A valving apparatus as described above has substantial advantages. Thevalve housing as well as the valve plug may be easily constructed due totheir cylindrical shape whereby precision work may be accomplished dueto said shape thus providing a better sealing characteristic than hasbeen accomplished heretofore in connection with flat valve slidemembers. Furthermore, the direct interconnection between the variousports without the interference of any guide means for a slide greatlyimproves the flow characteristics so that pressure drops are avoided.

Further, the location of the several ports relative to each other alsofacilitates achieving smooth flow characteristics.

Another advantage of the invention is seen in the provision that thecontrol plug has three distinct sections or members arranged in serieswith each other and functioning respectively in the suction passage, inthe pressure passage and again in the suction passage in that order.This greatly facilitates the displacement of the plunger as an integralunit and does not interfere with the alternating suction and pressurefunction of the pump cylinders 8 and 9. Another advantage of theinvention is seen in that the length of the control movement of the plugor the plug stroke is substantially reduced, which in turn, it has beenfound, by itself reduced the wear and tear by about 25 percent. Afurther reduction of wear and tear has been achieved according to theinvention due to the fact that the two outer passage ways have a gentlybent shape forming a knee of preferably less than whereas the centralpassage way is a straight passage way. A knee bent of about 75 has beenfound to be especially advantageous with regard to reducing wear andtear.

Moreover, it is advantageous to make the passage ways of uniformcross-sectional diameter and to provide the plug members withreplaceable inserts whereby the useful life of the entire structure maybe substantially increased. On the other hand, the plug membersthemselves may be made of synthetic material such as silicon rubberwhich facilitates the insertion and replacement of the inserts which arepreferably made of high wear resistant steel or the like.

The above combination of features not only reduces the wear and tear bya reduction of the length of the valve plug stroke but it also improvesthe flow characteristics and reduces the maintenance time whichheretofore has been necessary for the exchange of the valve slides withtheir respective guide means. Moreover, it is now possible to employmaintenance intervals of uniform duration.

Although the invention has been described with reference to a specificexample embodiment, it is to be understood, that it is intended to coverall modifications and equivalents within the scope of the appendedclaims.

What is claimed is:

1. A valving apparatus for interconnecting a double piston pump havingtwo cylinders with conveying conduit means and with supply means;comprising a cylindrical valve housing having a given length, saidhousing further having a first pair of aligned ports for connecting saidvalve housing to said two pump cylinders, 21 second pair of alignedports for connecting the valve housing to conveying conduit means, and athird pair of aligned ports for connecting the valve housing to saidsupply means, said ports being aligned at a pair of 2() planes extendingtransverse of the axis of said housing with each port of each pair ofports being aligned with a separate one of said planes, a piston valveplug mounted solely for axial movement in said cylindrical valvehousing, said plug having a central plug section (6) with a straightcylindrical passageway extending diametrically through the valve housingin a direction to interconnect ports of said first and second pair in acommon plane, a first outer plug section (5) with a bent cylindricalpassageway, and a second outer plug section (5) also with a bentcylindrical passageway, said first and second outer plug sections andsaid central plug section having together a length corresponding toabout three quarters of said given length of the cylindrical valvehousing, said first and second outer plug sections (5, 5 extending oneach side of said central passageway, each of said first and second bentcylindrical passageways including an angle within the range of about toabout so as to extend 2. The valving apparatus according to claim 1,wherein said plug sections from a unitary member made of silicon rubbermaterial, and wherein said passageways comprise highly wear resistantinserts made of steel.

UNITED STATES PATENT oFFIcE QE'HFICATE OF CORRECTION Patent No. 3 713Dated June 17 1975 lnventorgs) Horst Bender It is certified that errorappears in the aboveidentified patent and that said Letters Patent arehereby corrected as shown below:

Column 6, line 16 after "extend" insert:

--in a direction to interconnect ports of said first and third pairs ofports in a common plane, said passageways being axially spaced, wherebyin. one

axial position, said central passageway interconnects one port of saidfirst pair with one port of said second pair, while one of said outerbent passageways interconnects the other of said first pair with one ofsaid second pair, and whereby in another axial position said centralpassageway interconnects the other ports of said first and second pairs,while the other of said outer passageways interconnects said one of saidfirst pair of ports with the other of said third pair of ports, andmeans operatively connected to said valve plug for axially moving saidvalve plug in said valve housing so as to be compatible with thefunction of suction, pressure and suction in that order for each workcycle of the valve.

Signed and Sealed this twenty-sixth Day of August1975 [SEAL] A rtes t:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner uflarenrsand Trademarks

1. A valving apparatus for interconnecting a double piston pump havingtwo cylinders with conveying conduit means and with supply means;comprising a cylindrical valve housing having a given length, saidhousing further having a first pair of aligned ports for connecting saidvalve housing to said two pump cylinders, a second pair of aligned portsfor connecting the valve housing to conveying conduit means, and a thirdpair of aligned ports for connecting the valve housing to Said supplymeans, said ports being aligned at a pair of planes extending transverseof the axis of said housing with each port of each pair of ports beingaligned with a separate one of said planes, a piston valve plug mountedsolely for axial movement in said cylindrical valve housing, said plughaving a central plug section (6) with a straight cylindrical passagewayextending diametrically through the valve housing in a direction tointerconnect ports of said first and second pair in a common plane, afirst outer plug section (5) with a bent cylindrical passageway, and asecond outer plug section (5'') also with a bent cylindrical passageway,said first and second outer plug sections and said central plug sectionhaving together a length corresponding to about three quarters of saidgiven length of the cylindrical valve housing, said first and secondouter plug sections (5, 5'') extending on each side of said centralpassageway, each of said first and second bent cylindrical passagewaysincluding an angle within the range of about 75* to about 90* so as toextend
 2. The valving apparatus according to claim 1, wherein said plugsections from a unitary member made of silicon rubber material, andwherein said passageways comprise highly wear resistant inserts made ofsteel.